Patent GB-1485265-A (GB)
Title: Automatic testing of duplicated records
IPC: G11B25/00
Filed: 1974-11-18
Abstract: 1485265 Monitoring recordings EMI Ltd 18 Nov 1974 [17 Nov 1973 13 Nov 1974] 53468/73 and 49038/74 Heading H4J [Also in Division G5] In apparatus for testing for faults on a duplicated record of programme material, a store carries information of occurrences in the programme material having characteristics of faults and, when a duplicated record is played, discrimination is made using the store, to indicate possible faults on the duplicated record. A programme source 1 (e.g. a tape or other recorded or live source), when switches S1, S2 are set to contacts S1/1 and S2/1, is connected to the input of a detector 2 whose output is connected to a store 3. The detector 2 is responsive to possible duplication faults and other blemishes such as scratches, grit or blisters on a grooved disc record. It may include apparatus similar to those described in Specifications 1,177,934 or 1,125,412 and produce an output on occurrence of a possible fault or blemish. The output of detector 2 is registered in store 3 so that the time of occurrence in relation to programme material is known. This may be done by indicating in the store as elapsed time the interval between registered outputs of detector 2. Alternatively a time base in the form of clock pulses can be introduced and all operations synchronized. A duplicate record, as shown a grooved disc sound record, is placed on a turntable and pickup unit 4. Switch S1 connects the output of unit 4 to the input of detector 2 while switch S2 connects the output of detector 2 to one input of a comparator 5. An output of store 3 is connected to another input of comparator 5. A possible duplication fault or blemish provides a signal at output 6. A distinct or similar output could be given if a registered occurrence does not have a corresponding playback occurrence. The store 3 may be a random access store containing information on numerous sources of programme material. There may be multiplexing of the signal processing and recovery of stored information. Access may be required only when a possible fault is detected. There may be digital storage and manipulation. The apparatus may provide a print out of the number and type of gramophone records tested together with the test results. With grooved disc records, the press and matrices or stampers should be indicated on the record in a way discernable by the test apparatus. The test apparatus can be linked to the presses whose output is being tested to indicate and/or execute required remedial action or to stop the press. During pressing the record and/ or a label thereon is provided with coded markings capable of being read by a sensor coupled to store 3. The markings may comprise raised areas in the label region or in a region outside the label and may be produced by the stamper. They may be numerals formed from a special type font or be in binary form and produced from and produced from blocks of two sizes. Alternatively the coded markings may be printed instead of stamped or the trimmed edge of a disc may be marked. The apparatus may alternatively be used for video and for other recording material, e.g. tape. A test record may be played back at higher speed than normal, assuming the test information is modified as necessary.